1. In a bowl mix egg and sugar until it becomes soft and somewhat creamy.Now add the remaining wet ingredients i.e milk,oil and vanilla essence and mix well.

2. In a separate bowl mix the dry ingredients i.e all purpose flour and baking powder.Add this mix to the wet ingredients in batches and mix well until all the ingredients comes together to form a yellow creamy batter.

IMPORTANT : Do not over beat the batter.if you do so it will create air pockets and when you bake your cake it will have holes when u cut throught. This is applicable for all cake batter.

3.Divide the mixture into two equal portions.add the cocoa poder to one of the portion and mix well.

4. Now comes the assembling part.Sorry guys i couldn't take any photos.I know it would have been a great help for you if i have taken some pics.Anyway i will try my best to explain it well.Let me know if you want any help.

5.Lightly grease the baking pan with oil or butter.pour 3 tbps of the plain/yellow batter into the middle of the baking pan.Now pour 3 tbps of the cocoa batter above the plain/yellow batter into the center.next add the plain/yellow batter aobe the coco batter into the center.like this pour the batter into the center alternatively.

NOTE: Do not tilt or tap your baking pan to help them spread or dont even wait after pouring each batter to spread.it will spread by its own when you pour the batter alternatively.

6.Keep on pouring the batter until the batter is finished. At this stage you can find alternate colour rings formed.

7.Bake the batter for 40-45 min, until a tooth pick inserted comes out clean.